Screening for depression
Like blood pressure, cholesterol and glycaemia, mood should be routinely monitored in primary care because it is a health risk factor for other conditions, in addition to its direct effects on wellbeing. If a GP wishes to ensure that a patient is not left undiagnosed and if there is the means in the clinic to address patients’ needs (see Referring to psychoeducation and /or psychotherapy), GPs could consider routine depression screening e.g. of all new patients.
There are many screening instruments for depression.
The WHO-5 can be used as a first-line screening measure for depression. It is a well-validated measure for depression screening in primary care. It is easy to use and short with only five items, all positively framed (without mentioning “depression” explicitly). If a patient’s score is less than or equal to 13, they may be experiencing a depressive episode (80% sensitivity). In these patients, the diagnosis should be further explored by the GP.
Another screening tool for use in primary care is the PHQ-9, which allows the GP to identify the severity of the depressive symptoms and degree of functional impairment. This tool is also well-validated and is sensitive to change over time. A score of 5-9 suggests mild depression, 10-14 suggests moderate depression, and 15+ indicates severe depression. Particular attention should be paid to affirmative responses to item 9 (“thoughts that you would be better off dead or of hurting yourself in some way”).
The most important challenges in diagnosing depression are two-fold:
- Differentiate it from "feeling blue" that is, from normal or transient depressive feelings;
- Do not downplay the impact of even light symptoms of depression, which may be treatable;
There are several aspects of a depressive episode that indicate how severe it is, including apathy, emotional numbness, feelings of guilt, severe hopelessness, daily fluctuation in mood, suicidality, psychotic symptoms, and changes in personality.
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When reaching a diagnosis of depression, mood disorder due to organic conditions must be considered. Somatic and/or iatrogenic depression must be excluded and treated:
- endocrinological dysfunction such as hyper- or hypothyroidism, hyperparathyroidism, hypercortisolism;
- neurological disorders;
- viral infections;
- cancer and paraneoplastic syndromes;
- autoimmune reaction;
- pharmacological causes such as corticotherapy, benzodiazepine abuse and dependency, etc.